Responsibility for inspecting the properties rests with local councils.

The programme declared the latest figures to emerge from inspections in the rental sector showed problems were nationwide.

Figures supplied to 'RTÉ Investigates' under Freedom of Information legislation revealed only 4pc of rental properties were inspected last year and of those that were inspected, more than two thirds were not compliant with regulations.

Hayden said that steps now needed to be taken to protect tenants, starting with a certification system.

"A landlord should not be able to rent a property unless they have a certificate saying that property is fit for purpose," she said.

This echoed calls by Fianna Fail's Barry Cowen, who has said in recent days that an 'NCT-style' system is required in the rental sector to ensure that renters are guaranteed an acceptable standard of accomodation.

SIPTU firefighters also have renewed their demand for fire assessments in all properties following the extent of the risks in some buildings being highlighted.

"Such robust risk assessments take place in Northern Ireland and the United Kingdom, where they basically ask ‘what is behind the front door’ and identify particular hazards."

Dublin Fire Brigade Convenor, Shane McGill, said that it is clear that the fire risks in cities in particular have changed substantially and the fire service needs to respond accordingly.

"We are now dealing with multi-occupancy dwellings the likes of which have not been seen since the time of the tenements. As shown in the programme, there are many people living in these overcrowded and clearly unsafe units," he said.

"Adding to the problem is the large amount of combustible material evident in these dwellings. In addition, height restrictions have also been lifted on building in the city, which will lead to more high rise."